Signaling system



Nov. 7, 1933. H. M. BAscoM SIGNALING SYSTEM Filed April 6, 1927 2Sheets-Sheet l Nov. 7, 1933. H, M. BAscoM 1,933,650

SIGNALING SYSTEM Filed April 6, 1927 2 Sheets-Sheet 2 Patented Nov. 7,1933 UNITED STATES PATENT OFFICE SIGNALN G SYSTEM Henry M. Bascom,Brooklyn, N. Y., assignor to American Telephone and Telegraph Company, acorporation vof New York Application April 6, 1927. Serial No. 181,528

5Claims.

Thisinvention relates to indicating systems for the display at one pointof numbers, characters, or other symbols in response to thevactuation ofa suitable sending device at a distant point, and

more particularly to a system for indicating to an' object of thepresent invention is to provide a' system which makes use of shorterimpulses than heretofore, and of such duration that they may beeffectively.- transmitted over any circuits capable of transmittingvoice frequency currents. The invention has its preferred embodiment,specifically stated in a transmitting mechanism comprising a rotarydistributor adapted to connect a source of direct potential to itssegments inv rapid succession, said segments being associated,respectively, with contacts of a selector switch which is set by meansof a keyboard or dial in accordance with the number to be called and thebrushes of which are associated with the line,V whereby correspondingproperly spaced impulses are transmitted. At the receiving end of theline is a mechanism rftating in synchronism with thedistributor andcontrolling the light from a glow lamp, which is momentarily lighted byeach received impulse, to thereby set up the desired number on atranslucent screen by means of an optical system.

In the drawings Figure 1 illustrates the preferred form of the inventionjust referred to;

Fig. 2 is a front view of the ground glass screen of the indicator ofFig. 1 and shows projected thereon a four-digit number; e

Figs. 3 and 4 show analternative arrangement which differs principallyfrom the arrangement of Figs. 1 and 2 in that the indicator employs anopaque revolving disc instead of a cylinder on which appears atransparent arrow which is illuminated by the glow lamp and points to anumber on a stationary number plate surrounding the revolving disc, andthat, in the vdistributor, instead of the brush making direct contactwith the segments, it passes before vthe segments without actuallytouching them but sumi ciently close to cause an inductive disturbancein an associated output ampliiier circuit.

A detailed description of the invention will now be given.

` Referring to Fig. 1 of the drawings, 1 is a rotary distributor similarto equipment employed in printing telegraphy, etc. having a plurality of6, contact segments 2 wiped over by brush arm 3 driven at a rate ofspeed, of the order of 6000 revolutions per minute, through the mediumof a shaft 4 by a motor 5. A grounded battery is connected to the brusharm 3. The number of dstributor segments or contacts is determined bythe number of digits in the number to be transmitted and assuming a fourdigit number, a minimum of forty segments is required.

Associated with the distributor, and assuming provisions fortransmitting a four-digit number, are four selective switches 6-U, 6-T,6-H, and -TH, each of which consists of a bank of ten contacts, onecontact for each of the ten digits in the units, tens, hundreds, andthousands groups. These switches may be well-known stepby-step switchesused in automatic telephony,

'each having a movable contact arm or brush adapted to be set on anydesired one of the ten segments'by well-known means controlled by a dialor operators keyboard, not shown. Each of the forty switch contacts isindividually wired to one of the distributor segments, as shown.

The contact arms of the switches are connected in multiple to oneterminal of a winding of a transformer or repeating coil 7, the otherterminal of which is connected to ground.

It will now be obvious that for any setting of the switch arms on thecontacts of switches 6-U, 6-T, 6-H, and-TI-I, the brush arm 3 of thedistributor in making one complete revolution will close a circuit frombattery through the winding of transformer '7, four times, i. e., whenthe brush contacts with segments 1', 12, 23 and 9 34, therebytransmitting four alternating current impulses over the line L in whichmay be located amplifiers 9 and 11 for compensating i'or lossesoccasioned by the characteristics of the line and equipment, indicatedat 8 and 9, through 10o which the current impulses must pass. v

At the distant end of the line a second transformer 12 may be inserted,the secondary winding of which is connected to the terminals of a neontube or lamp 13, which has the property of responding promptly to theconnection and disconnection of electrical potential.

Surrounding the lamp 13 is an opaque cylinder 14 rotating on a shaft anddriven by a motor 16 which operates in synchronism with the motor no 5at the transmitting end of the line. Any suitable means well known inthe ait, such as used in printing telegraphy, may be employed formaintaining the two motors in synchronism, for example, a line 19terminating in synchronizing equipment 17 associated with each motor.may be utilized, but as the method of synchronizing forms no part ofthe present invention, it has not been described in any detail.

Around the circumference of the cylinder 14 are ,four rows oftranslucent digits 21-TH, 21-H, 21 T and 21-U and so staggered that aline drawn at any point on the cylinder, parallel to its axis, wouldpass through but one digit.

Behindihe neon lamp 13 is a reflector 20 arranged so as to cause anarrow band of light to shine onthe inner surface of the cylinderparallel to its axis.. Obviously, this band of light willilluminateffthe translucent digit which is oppositjthis .point in theCylinder at the instant the lamp is lighted.

Outside the cylinder and in line with each row of digits is a stationarylens 22 and in front of the row of lenses is a stationary ground glassscreen. The lenses 22 are so constructed and arranged as to project, onthe screen, the illuminated digit somewhat enlarged in size,

' Due to the speed of the distributor or impulser at the transmittingstation, which as before stated is of the order of revoluions persecond, the lamp 13 will be illuminated and extinguished so rapidly thatthe eye is unable to distinguish the flashes and it therefore appears asa steady light. Now if the cylinder 14 is in such a position that digit1 of row 21-TH is opposite the lamp 13 and reflector 20 at the instantdistributor arm 3 passes'over segment 1 of the distributor, and assumingthat the brush of selective switch G-TH is set on conact l, the digit 1will be illuminated and projected onthe screen 23, where it will bevisible to an operator and if the cylinder rotates in synchronism withthe arm of the transmitting distributor or impulser and the digits areproperly spaced around the circumference of the cylinder, this digitwill continue to be displayed so rapidly as to appear as a steady numberon the screen as long as the selective switch is set on contact 1 oruntil the circuit is broken in some other manner.

Now, for example, if the brushes of switches 6-TH, -H, 6-T and 6-Urepresenting the thousands, hundreds, tens and units digits of a numberto be transmitted are set on contacts l, 2, 3 and 4, respectively, totransmit the number 1234, these same respective digits on the cylinder14 will be successively illuminated as they pass in front of the lamp 13and will be individually projected on the screen 23, as shown in Fig. 2.

In case it is desired to transmit a party line code designation, such asthe letters W, R, M or- J, a fifth switch, not shown, and fouradditional segments would be required at lthe transmitting station and afifth row of translucent digits and a corresponding lens would berequired in connection with the indicator.

An alternative arrangement embodying the same fundamental principles aspreviously described is shown in Figs. 3 and 4.

Referring to Fig. 3 a single rotary segment at the outer end of thedistributor arm 3, driven by the"`motor 5, passes before each of thestationary contacts 2, but does not actually come in contact therewith.

In each lead from the segments to the contacts of the selector switches6--TH, 6--H, 6-T,

B-U and 6-C, an amplifier 23, 23', 232, etc.. irs introduced. Theseamplifiers consist of -a vacuum tube having a grid battery C and a platebattery B together with an associated output coil 25. 'I'he rotatingsegment of the distributor is connected to battery andas it passesbefore any one of the stationary segments, the potential of thatsegment, as determined by the C battery of the corresponding amplifier23 is changed by virtue of the fact that the high resistance R, whichserves as a grid leak, is introduced in series with the grid battery.

The battery connected to the rotary segment is, of course, of adifferent potential than the C battery of the amplifier, andconsequently, the potential on the grid G of any particular tube isincreased when the rotating member of the distributor passes thestationary contact to which the grid is connected and is restored tonormal after the rotating member has passed by the segment in question.

This change of grid potential causes a single ampliedimpulse to be sentto the associated selector switch, such as -TH. The switches -TI-I, 6-H,etc. are set in accordanceI with any desired number, and party linedesignation, as, for example, 1234.1, bythe action of a dial oroperators keyboard as previously mentioned.

From the brushes or contact arms of the switches 6--'IH, etc. leads arerun to vacuum tubes 244, 243, etc., which serve as one-way paths for thecurrent impulses. The plate circuits of all these tubes are connected inparallel with output transformer 7.

Without the use of these one-way tubes in the selector switch brushleads, it would be possible, for example, for a pulse incoming tocontact l of the switch 6--TH to cause a change in potential on contact2 of 6-H, contact 3 of S-T, contact 4 of 6-U and contact J of 6-C,thereby effecting, falsely, the contacts of other multiple selectiveswitches which are also adapted to control impulses from the commondistributor or impulser 1.

The one-Way tubes 24, etc., are provided with a C battery C2 and aresistance R2 for the purpose of maintaining the potential of theassociated selective switch brush at normal while it is being rotatedduring the setting operation.

The secondary winding of the transformer 7 is connected to the line Lwhich may be equipped with additional amplifiers 9 and 11.

Wires from the secondary winding of transformer 12 are run to acircular-shaped neon tube or lamp 13 which is lighted `for each digittransmitted as in the previously described arrangement.

The neon lamp is inclosed in a casing 20. In front of the lamp is aplate 14 which is opaque except for a transparent arrow 22. This plateis rotated by a motor 16 which operates in synchronism with the motor 5of the transmitting distributor or impulser l.

A stationary circular number plate 21 is mounted on the casing 20 andsurrounding the rotating plate 14. On this number plate is indicated theunits, tens, hundreds and thousands digit of a four-digit number andalso the four party letters, W, R, M and J, or any other desired code.

With motors 5 and 16 operating in synchronism the transparent varrow issteadily illuminated and points to the digit or a letter correspondingto the setting of the selective switch. Five steady illuminated arrows(Fig. 4) will point to the digits and letter corresponding to thesetting of the selective switches 6-TH, 6-H, etc.

It is understood that the distributor of either Fig. 1 or Fig. 3 mayserve as a common impulse device for a number of groups of selectorswitches 6.

What is claimed is:

1. In a telephone call indicating system, a transmitting station, areceiving station, a line interconnecting them, a mechanism at thetransmitting station including a rotary distributor for selectivelytransmitting to the line a cyclically recurring succession of electricalimpulses selectively spaced within the cycle in accordance with apredetermined code corresponding to a plurality of characters which itis desired to simultaneously indicate at the receiving station, saidcyclic impulses being transmitted at such a rate that they will berepeated within a time interval not greater than the period ofpersistence of vision, and a mechanism at the receiving stationoperating in synchronism with the transmitting distributor forluminously displaying in a row, due to persistence in vision, theplurality of characters transmitted.

2. In a telephone call indicating system, a transmitting station, areceiving station, a line interconnecting them, a mechanism at thetransmitting station including a rotary distributor for selectivelytransmitting to the line a cyclically recurring succession of electricalimpulses selectively spaced within the cycle in accordance witha,predetermined code corresponding to a plurality of characters which itis desired to simultaneously indicate at the receiving station, saidcyclic impulses being transmitted at such a rate that they will berepeated within a time interval not greater than the period ofpersistence of vision, and a mechanism at the receiving stationincluding an opaque cylinder rotating in synchronism with thedistributor at the transmitting station, a plurality of staggered setsof transparent openings arranged in circumferential rows in the cylinderwall, the openings of each set having different characteristic shapescorresponding to the characters to be indicated, a glow lamp connectedto the line and positioned within the cylinder, and stationary meansassociated with the cylinder for restricting instanianeous visibility ofsaid openings to a single row.

3. In a telephone call indicating system, a transmitting station, areceiving station, a line' interconnecting them, means at thetransmitting station for producing and selectively transmitting acyclically recurring succession of electrical impulses spaced within thecycle in accordance with a predetermined code corresponding to aplurality of characters which it is desired to simultaneously indicateat the receiving station, said impulses being transmitted at such a ratethat they will be repeated cyclically within a time interval not greaterthan the period of persistence of vision, said means including arotating distributor for transmitting the impulses to the line and aselector switch adapted to be set to determine the spacing of theimpulses transmitted, and a mechanism at the receiving station includingan opaque cylinder rotating in synchronism with the distributor at thetransmitting station, variously shaped transparent openings in thecylinder wall each representing one of the characters which are to betransmitted, a glow lamp connected to the line and so adapted andpositioned within the cylinder as to illuminate said transparentopenings with each impulse, and means including a screenand a system oflenses positioned adjacent said cylinder, said openings being sodisposed around the Wall' of said cylinder and said lens system andscreen so disposed with respect to the cylinder that during thetransmission of character impulses the plurality of characterscorresponding to the impulses transmitted will appear in a row on saidscreen.

4. In a telephone call indicating system, a line, means at one endthereof for producing and transmitting to said line a cyclicallyrecurring succession of electrical impulses selectively spaced withinthe cycle in accordance with a predetermined code corresponding to aplurality of characters which it is desired to simultaneously indicateat the other end of the line, said means including a rotating device fortransmitting said impulses at such a rate that each cyclic impulse willbe repeated within a time interval not greater than the period ofpersistence of vision, an indicating mechanism at the other end of theline including a rotatable opaque screen, means for rotating said screenin synchronism with the means at the transmitting station, a transparentindicator opening in the opaque screen, an electric glow lamp associatedwith the line and made active by said line impulses, said lamp being sopositioned with respect to said screen as to illuminate said opening,and stationary means cooperating with said rotating screen, and bearingrepresentations of the characters which are to be transmitted, saidcharacter representations being so positioned that when the opening insaid screen is illuminated, character representations on said stationarymembers will be simultaneously indicated, due to the persistence ofvision, which correspond to the code of impulses transmitted.

5. In a telephone call indicator for transmitting and indicatingcharacters, means including a rotating member for producing andselectively transmitting to a line a cyclically recurring succession ofelectrical impulses selectively spaced within the cycle in accordancewith a plurality of desired characters to be transmitted and at a cyclicrate such that each impulse will be repeated within a time interval notgreater than the period of persistence of vision and means for receivingsaid impulses and indicating said character comprising an opaque screenrevolving in synchronism with the rotating member at the transmitter, aplurality of staggered rows of transparent openings in said screen, theopenings of each row being of various shapes to represent the characterstransmitted, a glow lamp responsive to the line impulses and sopositioned as to illuminate the transparent openings and a stationarymember so positioned with respect to the screen as to restrictinstantaneous visibility of said illuminated openings to a single row.

HENRY M. BASCOM.

